Robert F. Kennedy Jr.’s estranged wife, Mary, who battled her husband’s rumored philandering by turning to alcohol and prescription drugs, hanged herself in a barn on their Westchester estate today, sources told The Post.

The 52-year-old mother of four — the latest victim of a family dynasty cursed with tragedies — may have taken her own life because she was haunted by her broken marriage, her friends lamented. “She was deeply troubled, abusing alcohol and prescription meds,” a close family friend said. “She had cause. She was used up and tossed away by Bobby. That was awful.”

Officials refused to elaborate on her death and said it would be investigated with the help of the Westchester Medical Examiner’s Office. Bedford police responded at 1:36 p.m. to a report of a “possible unattended death” — meaning there were no witnesses — at the estate.

Mary was found “inside an out-building on that property,” police said in a statement. There are several sheds behind the home — some hold garden tools and another is a falcon house — on a slope leading to a lake.

The Kennedy family dealt stoically with the latest in the long line of shocking deaths. “We deeply regret the death of our beloved sister Mary, whose radiant and creative spirit will be sorely missed by those who loved her,” the family said in a statement. “Our heart goes out to her children, who she loved without reservation. We have no further comment at this time.” A grim-faced Kennedy showed up at the house around 8 p.m.

The third of 11 children of former US senator, attorney general and presidential candidate Robert Francis Kennedy, he married Mary Richardson in 1994 one month after his first marriage ended after 12 years. The wedding ceremony took place aboard a research vessel on the Hudson River, a fitting location for the couple, who were environmental advocates.

A family friend said Mary had known the Kennedy clan long before she married Bobby and had been a close friend of his sister, Mary — known as “Kerry” — since they were 15-year-olds. “She had grown up with the Kennedy family, having been Kerry’s best friend since they were teenagers.” But the marriage broke down amid reports of her addiction and rumors of his involvement with other women.

According to The New York Times, Mary R. Kennedy, the estranged wife of Robert F. Kennedy Jr., was found dead on Wednesday at the family’s home in Bedford, N.Y. She was 52. Ms. Kennedy’s death was confirmed in a statement from her family, who did not comment on the circumstances.

Two people with knowledge of the matter said that Ms. Kennedy’s body was found hanging, and one of them said that it was discovered in a barn behind the house and that she had left a note. The other person said that the authorities who responded to the scene had cut her down and tried to revive her.

The Bedford Police Department said only that it had investigated a “possible unattended death” in an outbuilding at the home.

Kieran O’Leary, a spokesman for Westchester County, said an autopsy was scheduled for Thursday morning. Born Mary Richardson, Ms. Kennedy joined one of America’s foremost political families in 1994, in a marriage ceremony aboard a boat on the Hudson River, near Stony Point, N.Y.

At the time, she was an architectural designer at Parish-Hadley Associates in New York. The couple had four children together; Mr. Kennedy had two from a previous marriage. Although news outlets have reported that Mary Kennedy and her husband had become estranged and that he filed for divorce in 2010, her lawyer, Kerry A. Lawrence, said on Wednesday that they were not divorced.

In 2010, Ms. Kennedy was arrested twice — once on a charge of driving while intoxicated, and later on a charge of driving under the influence of prescription medication. The first charge was reduced to a violation, Mr. Lawrence said; Ms. Kennedy was ordered to undergo alcohol treatment and her license was suspended for 90 days. The prescription drug charges were dismissed, Mr. Lawrence said.

Ms. Kennedy’s family, in a statement on Wednesday, recalled her “radiant and creative spirit” and the love she had for her children, “without reservation.” A statement released by Mr. Kennedy’s family praised her as a “genius at friendship, a tremendously gifted architect and a pioneer and relentless advocate of green design.”

She had advocated treatment and research in the study of food allergies and asthma, the statement said, and was one of the founders of the Food Allergy Initiative, which raises money for food allergy research. Ms. Kennedy’s death is another in a series of personal tragedies for the family. Her husband was the third of 11 children born to Ethel Kennedy and Senator Robert F. Kennedy, who was assassinated in 1968.

Mr. Kennedy arrived at the property in Bedford around 8:15 p.m. on Wednesday, appearing to grimace as he entered the home. A prominent environmental lawyer, Mr. Kennedy is the president of the Waterkeeper Alliance. Outside the sprawling, forested property, neighbors said they had rarely seen the family.

The house is set back from the road. Several “No Trespassing” signs lined the edge of the property. Kim Fraioli, 45, a trauma therapist who has lived next door for 10 years, said she had never interacted with the Kennedys. She knew they were her neighbors only because her real estate agent had said so.

Around 7:30 p.m., two women entered the property, one carrying flowers, the other hauling a tray and a bag of food. “This is terrible,” the woman with the flowers said, breaking into tears. “We don’t need this.”

Robert F Kennedy Jr. and Mary Richardson Kennedy. Photo Credit: NY Daily NewsMary Richardson Kennedy, house builder Jim Blansfield and Robert Kennedy Jr. posing in the house where Mary was found dead Wednesday. Story Credit: New York Post – LARRY CELONA, EMILY SMITH and ANDY SOLTIS / Photo Credit: New York Post via JIMFUHRMANN.COMActress Cheryl Hines and Robert F. Kennedy Jr. Photo Credit: ZimbioRobert F Kennedy Jr. and Mary Richardson Kennedy’s house in Mt Kisco. Story Credit: New York Post – LARRY CELONA, EMILY SMITH and ANDY SOLTIS / Photo Credit: New York Post via JIMFUHRMANN.COMInside the house where Mary Kennedy was found dead. Story Credit: New York Post – LARRY CELONA, EMILY SMITH and ANDY SOLTIS / Photo Credit: New York Post via JIMFUHRMANN.COM